Method and system for directing fuel flow to an engine

Abstract

Systems and methods for directing fuel flow to an engine when the engine is in an electronic manual override mode are described herein. In accordance with an aspect, a commanded fuel flow to the engine is determined from a fuel schedule based on the position on an engine control lever; a limit is applied on the commanded fuel flow when the commanded fuel flow exceeds a maximum fuel flow threshold; and fuel flow is directed to the engine based on the commanded fuel flow.

1 . A method of directing fuel flow to an engine for an aircraft when the engine is in an electronic manual override mode, the method comprising:
 determining a commanded fuel flow to the engine from a fuel schedule based on a position of an engine control lever for controlling the engine;   applying a limit on the commanded fuel flow when the commanded fuel flow exceeds a maximum fuel flow threshold; and   directing fuel flow to the engine based on the commanded fuel flow while maintaining fuel flow within the limit.   
     
     
         2 . The method of  claim 1 , wherein the maximum fuel flow threshold varies as a function of one or more operating conditions. 
     
     
         3 . The method of  claim 2 , wherein the one or more operating conditions comprise one or more of aircraft speed, air temperature, altitude and engine extractions. 
     
     
         4 . The method of  claim 1 , further comprising selecting the fuel schedule based on one or more operating conditions. 
     
     
         5 . The method of  claim 3 , further comprising obtaining an altitude of the aircraft, and wherein selecting the fuel schedule comprises selecting the fuel schedule based on the altitude of the aircraft as the one or more operating conditions. 
     
     
         6 . The method of  claim 1 , wherein the maximum fuel flow threshold corresponds to a fuel flow amount occurring at a predetermined value above a maximum power rating of the engine. 
     
     
         7 . The method of  claim 1 , further comprising detecting the electronic manual override mode of the engine. 
     
     
         8 . The method of  claim 1 , further comprising:
 detecting a fault of a control system for controlling the engine; and   triggering the electronic manual override mode.   
     
     
         9 . A system for directing fuel flow to an engine for an aircraft when the engine is in an electronic manual override mode, the system comprising:
 a processing unit; and   a non-transitory computer-readable memory having stored thereon program instructions executable by the processing unit for:
 determining a commanded fuel flow to the engine from a fuel schedule based on a position of an engine control lever for controlling the engine; 
 applying a limit on the commanded fuel flow when the commanded fuel flow exceeds a maximum fuel flow threshold; and 
 directing fuel flow to the engine based on the commanded fuel flow while maintaining fuel flow within the limit. 
   
     
     
         10 . The system of  claim 9 , wherein the maximum fuel flow threshold varies as a function of one or more operating conditions. 
     
     
         11 . The system of  claim 10 , wherein the one or more operating conditions comprise one or more of aircraft speed, air temperature, altitude and engine extractions. 
     
     
         12 . The system of  claim 9 , wherein the program instructions are further executable by the processing unit for selecting the fuel schedule based on one or more operating conditions. 
     
     
         13 . The system of  claim 12 , wherein the program instructions are further executable by the processing unit for obtaining an altitude of the aircraft, and wherein selecting the fuel schedule comprises selecting the fuel schedule based on the altitude of the aircraft as the one or more operating conditions. 
     
     
         14 . The system of  claim 9 , wherein the maximum fuel flow threshold corresponds to a fuel flow amount occurring at a predetermined value above a maximum power rating of the engine. 
     
     
         15 . The system of  claim 9 , wherein the program instructions are further executable by the processing unit for detecting the electronic manual override mode of the engine. 
     
     
         16 . The system of  claim 9 , wherein the program instructions are further executable by the processing unit for:
 detecting a fault of a control system for controlling the engine; and   triggering the electronic manual override mode.   
     
     
         17 . A method of directing fuel flow to an engine for an aircraft when the engine is in an electronic manual override mode, the method comprising:
 determining a commanded fuel flow to the engine based on a position of an engine control lever for controlling the engine;   monitoring a temperature of the engine;   applying a limit on the commanded fuel flow based on the temperature of the engine to maintain the temperature of the engine within a maximum temperature threshold; and   directing fuel flow to the engine based on the commanded fuel flow while maintaining fuel flow within the limit.   
     
     
         18 . The method of  claim 15 , wherein the maximum temperature threshold corresponds to a temperature occurring at a maximum power rating of the engine. 
     
     
         19 . The method of  claim 17 , further comprising detecting the electronic manual override mode of the engine. 
     
     
         20 . The method of  claim 17 , further comprising:
 detecting a fault of a control system for controlling the engine; and   triggering the electronic manual override mode.